1. Field of the Invention
The present invention is directed to a novel processes for preparing certain cysteine protease inhibitors.
2. State of the Art
WO 03/075836 and Applicant's provisional application Ser. No. 60/504,680 filed on Sep. 18, 2003, disclose certain cysteine protease inhibitors that are useful in the treatment of diseases such as osteoporosis, certain autoimmune disorders, including, but not limited to juvenile onset diabetes, multiple sclerosis, pemphigus vulgaris, Graves' disease, myasthenia gravis, systemic lupus erythemotasus, rheumatoid arthritis and Hashimoto's thyroiditis, allergic disorders, including, but not limited to asthma; and allogeneic immune responses, including, but not limited to, rejection of organ transplants or tissue grafts.
The processes disclosed to prepare the compounds in these applications are unattractive for large scale synthesis of these compounds since they are lengthy and/or involve harsh reaction conditions which are unsuitable for a wide variety of substitutents. Accordingly, there is a need for synthetic processes that are facile and/or utilize reaction conditions that are amenable to a variety of substituents and therefore attractive on commercial scale. The present invention fulfills this and related needs.